1. Field of the Invention
The present invention relates to a lateral high-voltage transistor and a method for manufacturing the lateral high-voltage transistor.
2. Description of the Background Art
As a semiconductor device for use in, for example, power applications which requires high breakdown voltage characteristics, a lateral high-voltage transistor such as a lateral MOSFET has been known.
A conventional lateral high-voltage transistor involves a problem that, when a high voltage is applied in an OFF state, depletion of a drift region is insufficient, and breakdown voltage characteristics are deteriorated. Therefore, for example, in Japanese Patent Application Laid-Open No. 2000-114520, the drift region is formed of a stripe-shaped diffusion layer to thereby ensure depletion of the drift region, thus improving the breakdown voltage characteristics.
A conventional lateral high-voltage transistor involves a problem that, in a case where a voltage equal to or higher than a threshold voltage is applied to the gate to put the transistor into an ON state under conditions that a high voltage is applied between the drain and source, a current flowing through a channel leaks to a substrate, which reduces a drain current.